Principle and Performance Analysis of the Levenberg–Marquardt Algorithm in WMS Spectral Line Fitting

Calibration-free wavelength modulation spectroscopy (WMS) is an efficient technique for trace gas monitoring. It widely used due to its resistance light intensity fluctuations, strong suppression of low-frequency noise, fast response time, and excellent environmental adaptability. The calibration-free WMS often employs the Levenberg–Marquardt algorithm spectral fitting retrieve characteristics. However, best our knowledge, analysis main factors affecting operational effectiveness in has merely been reported. In this paper, we have systematically analyzed algorithm’s operating mechanism WMS-2f/1f. results show that number parameters estimation errors initial are limiting retrieval accuracy algorithm, which provides some important guidelines subsequent optimization scheme.